El sistema sedimentario del río Bermejo

IRIONDO, MARTÍN; ORFEO, OSCAR

Aportes sedimentológicos a la geología del noroeste argentino

SCS Publisher

Lugar: Salta, Argentina; Año: 2012; p. 111 - 118

ABSTRACT The Bermejo River is one of the most important tributaries of the Paraná and La Plata rivers. It conveys about 100 million tons of suspended sediments per year, which is the half of the total volume of Río de la Plata basin. The Bermejo system is composed by two well defined sub-basins: a mountain region and a mega-fan. The mountain sub-basin is formed by several important tributaries; the dominant mechanism of sediment supply to the channels is the generalized occurrence of mudflows during the humid season of the year; the channel beds are composed of pebbles and sand in two well defined populations. The mega-fan was built by channel avulsions in the upper part and avulsions and overflows in the distal region; the Bermejo channel conveys clayey silt in suspension and very fine sand by creep and saltation. The conspicuous sedimentary phenomenon inside the mega-fan is that the concentration of suspended sediment increases downstream during the low water season.